1. Field of the Invention
The present invention relates to hearing aids. The invention more specifically relates to hearing aid systems having a dual mode wireless radio.
In the context of the present disclosure, a hearing aid should be understood as a small, microelectronic device designed to be worn behind or in a human ear of a hearing-impaired user. A hearing aid system may be monaural and comprise only one hearing aid or be binaural and comprise two hearing aids. Prior to use, the hearing aid is adjusted by a hearing aid fitter according to a prescription. The prescription is based on a hearing test, resulting in a so-called audiogram, of the performance of the hearing-impaired user's unaided hearing. The prescription is developed to reach a setting where the hearing aid will alleviate a hearing loss by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit. A hearing aid comprises one or more microphones, a microelectronic circuit comprising a signal processor, and an acoustic output transducer. The signal processor is preferably a digital signal processor. The hearing aid is enclosed in a casing suitable for fitting behind or in a human ear.
As the name suggests, Behind-The-Ear (BTE) hearing aids are worn behind the ear. To be more precise, an electronics unit comprising a housing containing the major electronics parts thereof is worn behind the ear. An earpiece for emitting sound to the hearing aid user is worn in the ear, e.g. in the concha or the ear canal. In a traditional BTE hearing aid, a sound tube is used because the output transducer, which in hearing aid terminology is normally referred to as the receiver, is located in the housing of the electronics unit. In some modern types of hearing aids a conducting member comprising electrical conductors is used, because the receiver is placed in the earpiece in the ear. Such hearing aids are commonly referred to as Receiver-In-The-Ear (RITE) hearing aids. In a specific type of RITE hearing aids the receiver is placed inside the ear canal. This is known as Receiver-In-Canal (RIC) hearing aids.
In-The-Ear (ITE) hearing aids are designed for arrangement in the ear, normally in the funnel-shaped outer part of the ear canal. In a specific type of ITE hearing aids the hearing aid is placed substantially inside the ear canal. This type is known as Completely-In-Canal (CIC) hearing aids. This type of hearing aid requires a very compact design in order to allow it to be arranged in the ear canal, while accommodating the components necessary for operation of the hearing aid.
State-of-the-art hearing aids are usually designed to accept more than one signal source for advanced functionalities for the purpose of amplifying, conditioning and reproducing them by virtue of the hearing aid circuitry. Such signal sources are e.g. televisions, mp3 players and mobile phones.
Some hearing aids have means for connecting external equipment to the hearing aid circuitry, such as FM-receivers, Bluetooth® receivers, cables etc. Such external equipment enables communication with the hearing aid in various ways. An FM-receiver may be connected for use in public address situations where a speaker is wearing a microphone with a wireless FM transmitter. A Bluetooth® receiver may be used for streaming audio signals from a mobile telephone or the like.
Some hearing aid types also comprise internal wireless receivers such as e.g. inductive receivers. Most of these wireless receivers draw their power directly from the hearing aid battery.
Prolonged use of external equipment or wireless receivers known in the art may lead to rapid depletion of the hearing aid battery necessitating frequent battery changes and adding to the cost of operation of the hearing aid. Receiver types having integral power supplies comprising a separate battery add to the weight, size and complexity of the receiver. More power-efficient wireless equipment would thus be of great benefit to hearing aid users.
In some hearing aid types a wireless link is provided between the two hearing aids of a binaural hearing aid system. In this case an inductive wireless link is particularly advantageous because the power consumption can be very low over such small distances. Further, since the hearing aids of the binaural hearing aid system are adapted to be worn in or at a left and right ear of a hearing aid user, it is advantageous to employ an inductive wireless link because the magnetic field signals transmitted by the inductive wireless link are not significantly attenuated by the head of the hearing aid user.
In yet other types of hearing aids an inductive radio is used to receive audio signals from external signal sources or external relay devices. In this type of hearing aid systems the external signal source or the external relay device must be within close range (typically less than one meter) because the transmission and reception range of the inductive radio falls off approximately with the distance raised to the third power.
2. The Prior Art
WO-A1-2010043223 discloses a DVD player, which is connected to a television set, a first external device, a second external device and a binaural hearing aid system, wherein the first external device is dedicated for encoding and wirelessly transmitting an audio signal, provided by the DVD player, to the second external device, which is adapted for relaying wirelessly the audio signal further on to the binaural hearing aid system. The second external device ensures that the wireless signal transmission consumes a minimum of electrical power in the hearing aids.
It is a feature of the present invention to provide a hearing aid with improved wireless link means, hereby providing a hearing aid with a longer wireless range while maintaining a small hearing aid size and low power consumption.
It is still another feature of the present invention to provide an improved method for transmitting and receiving wireless signals.